Added a makeInvisible call to Face Unlock

This makes it so that the view is hidden immediately when
a call to stop is made.  This also changes the call in onPause to
only stop and not go to the backup because we still want Face Unlock
to show as the view is being dragged down.

Change-Id: I66d8fc24e82dc3a0155f7d59d8ced932cb584660

core/java/com/android/internal/policy/IFaceLockInterface.aidl

@@ -23,6 +23,7 @@ interface IFaceLockInterface {
     void startUi(IBinder containingWindowToken, int x, int y, int width, int height,
             boolean useLiveliness);
     void stopUi();
+    void makeInvisible();
     void registerCallback(IFaceLockCallback cb);
     void unregisterCallback(IFaceLockCallback cb);
 }

policy/src/com/android/internal/policy/impl/keyguard/FaceUnlock.java

@@ -151,6 +151,14 @@ public class FaceUnlock implements BiometricSensorUnlock, Handler.Callback {
         }
 
         boolean mWasRunning = mIsRunning;
+        try {
+            if (mService != null) {
+                mService.makeInvisible();
+            }
+        } catch (RemoteException e) {
+            Log.e(TAG, "Caught exception making Face Unlock invisible: " + e.toString());
+        }
+
         stopUi();
 
         if (mBoundToService) {

policy/src/com/android/internal/policy/impl/keyguard/KeyguardFaceUnlockView.java

@@ -85,7 +85,7 @@ public class KeyguardFaceUnlockView extends LinearLayout implements KeyguardSecu
     public void onPause() {
         if (DEBUG) Log.d(TAG, "onPause()");
         if (mBiometricUnlock != null) {
-            mBiometricUnlock.stopAndShowBackup();
+            mBiometricUnlock.stop();
         }
         KeyguardUpdateMonitor.getInstance(mContext).removeCallback(mUpdateCallback);
     }